Underbody Convective Blanket and Method for Manufacturing Thereof

ABSTRACT

A convective underbody blanket has a head portion and a body portion. Provided at the head portion is a non-inflatable head area surrounded by a channel that has arranged thereat at least one row of air apertures that are oriented toward the non-inflatable head area when the channel is inflated. At the body portion there is provided a non-inflatable body area. Along each longitudinal side of the body area there is at least one longitudinal channel. Each of the longitudinal channels is in fluid communication with the channel that surrounds the non-inflatable head area. The longitudinal channels that sandwich the non-inflatable body area extend substantially along the length of the non-inflatable body area and are in fluid communication with each other by way of a cross channel formed at the foot end of the blanket.

FIELD OF THE INVENTION

The present invention relates to convective warming blankets and moreparticularly to an underbody blanket for convectively warming both thehead and the body of the patient.

BACKGROUND OF THE INVENTION

There are underbody convective blankets in the market. One of thoseblankets is described in U.S. Pat. No. 6,511,501. However, the '501blanket is not meant to provide warmth to the head of the patient viaconvection. There are moreover a number of other blankets representedfor example by U.S. Pat. Nos. 5,360,439, 5,384,924, 5,514,169, 5,632,769and 5,839,133 that specifically have a recess at the head end of theblanket whereby the head of the patient lies.

There are some convective blankets that could warm the head of thepatient. However, most of those blankets are for covering the body ofthe patient. An example of such blankets is disclosed in U.S. Pat. No.5,928,274 in which the head portion of the blanket has a recess so thatonly the head of the patient is not covered by the blanket.

Also with respect to the prior art convective blankets, the apertures orholes whereby the warm air is output from the blanket usually arepre-punched before the two layers of the blanket are bonded so that theapertures are substantially evenly distributed across the sheet of theblanket that outputs the warm air. That being the case, the heated airoutput from the blanket is directed to the patient without much focus.Furthermore, for the prior art underbody blankets, at least with respectto those that are full body convective blankets, the channels thatextend longitudinally along the blanket usually would extend all the wayto the foot end of the blanket, so that the air input to the blanketflows substantially in only one direction. This means that by the timethat the heated air gets to the foot end of the blanket, the warmth ofthe air has substantially diminished. Accordingly, there is atemperature gradient difference between the heated air output proximallyto the air inlet port and the heated air output distally from the airinlet port.

A need therefore exists for a new type of underbody blanket that warmsthe head, as well as the body of the patient, with the warm aircirculating about the blanket to maintain an even temperaturethroughout, and when output from the blanket, is focused to the patient.

SUMMARY OF THE PRESENT INVENTION

The convective blanket of the instant invention is an underbody blanketthat is designed to support the entire body of the patient, includingthe head of the patient. As such, the blanket is configured to have ahead portion and a body portion, with the head portion extending fromthe head end of the blanket to the beginning of the body portion, whichextends to the foot end of the blanket.

To receive the head of the patient, there is formed at the head portiona non-inflatable head area. This head area is encircled by a channel orthrough passage where fluid such as air passes. There are a number ofrows of air holes or apertures that are arranged in a configuration thatfollows the outline of the non-inflatable head area. The rows ofapertures may be substantially in parallel and are arranged such that ifthe channel were inflated, the apertures would be oriented towards thenon-inflatable head area to substantially point towards the head of thepatient. Accordingly, air output from the apertures is directed to thehead of the patient. When the channel is inflated and heated aircirculates through the channel at the head portion, the patient's head,which is received in the non-inflatable head area, is bathed by the warmair output from the apertures.

Extending from the head portion is the body portion. There is formed inthe body portion a non-inflatable body area onto which the body of thepatient, or at least a portion of the body of the patient, is received.There are extending along each longitudinal side of the non-inflatablebody area a number of channels, in this embodiment two adjacent channelsseparated by a longitudinal seal. There is formed at each of thechannels at least one row of air apertures arranged along the channelssuch that when the channels are inflated, these apertures would point toor be oriented toward the non-inflatable body area. Air output from theapertures accordingly would be directed to the patient's body lying onthe non-inflatable body area. By providing multiple channels along eachlongitudinal sides of the non-inflatable body area, the height orvertical profile of the blanket when fully inflated is reduced. Thelongitudinal channels that run along the sides of the non-inflatablebody area extend substantially towards the distal end of thenon-inflatable body area.

A cross channel is formed between the distal end of the non-inflatablebody area and the foot end of the blanket to establish a fluid path orthrough passage between the sets of adjacent channels that extendlongitudinally along the non-inflatable body area.

By thus connecting the longitudinal channels that sandwich thenon-inflatable body area with both the cross section at the foot end ofthe blanket and the channel that circumscribes the non-inflatable headarea of the blanket, continuous through passages are establishedthroughout the convective blanket so that air input to the blanket viaany one of the open channels is circulated throughout the blanket withthe heated air being output from the various rows of apertures directlyto the desired areas of the patient lying on top of the blanket.

To input air to the blanket, at least one air inlet is provided.However, for the exemplar blanket embodiment, three air inlets may beprovided. These air inlets may be configured the same as that disclosedin U.S. application Ser. No. 11/401,957 entitled “Hose Retainer forThermal Blanket”, assigned to the same assignee as the instantinvention. The disclosure of the '957 application is incorporated byreference herein. By providing two of the air inlets at the respectiveshoulders of the blanket and an air inlet at the foot of the blanket,air may be input to the blanket at any one of those different locationson the blanket.

To eliminate bodily fluid from the patient that may collect at thenon-inflatable body area of the blanket, at least one optional fluidabsorption pad may be provided at the patient body area.

There are provided at each longitudinal side of the blanket a flap thatallows the blanket to be adhered or attached to the bed or operationtable onto which the blanket is placed.

With the inventive underbody blanket, the entire body of the patientlying on the blanket is accessible.

So that a surgeon operating on the patient is not heated by the warmair, another embodiment of the blanket of the instant inventioneliminates a number of air apertures along the longitudinal channelsthat sandwich the non-inflatable body area of the blanket. In thisembodiment, the respective rows of apertures that extend along thelongitudinal channels adjacent to the non-inflatable body area arepartitioned into at least two sets of apertures that are separated by anon-apertured section. The non-apertured section is located along theblanket at an area where the surgeon usually positions when he or sheoperates on the patient lying on top of the inventive blanket.

A further embodiment of the blanket of the instant invention focuses onconcentrating the apertures to particular parts of the blanket so thatonly corresponding portions of the body of the patient is bathed by theair output from the blanket. A first variant of this embodiment is theprovision of respective rows of apertures along the longitudinalchannels that sandwich the non-inflatable body area only at the upperportion of the blanket so that only the upper body or chest area of thepatient is bathed by the output air. Another variant of the embodimenthas the apertures provided only at the lower portion of the blanketalong the longitudinal channels that sandwich the non-inflatable bodyarea so that only the lower body and/or foot portion of the patient isbathed by air output from the blanket. All other features of theinvention remain the same for this further embodiment.

To manufacture the inventive blanket, two sheets of flexible airimpermeable materials are sealed or bonded together at selectivelocations to form the various channels and non-inflatable head and bodyareas. Before bonding, the sheet to be in contact with the patient isselectively punched with pre-configured rows of apertures, so that oncebonded to the other sheet, the apertures that are at the variouschannels would be arranged such that when air is input to the blanketand the channels are inflated, the apertures would point towards thenon-inflatable areas for directing the output heated air thereat.

The present invention is therefore an underbody convective blanket thatcomprises a first air impermeable flexible sheet having a plurality ofapertures selectively bonded to a second air impermeable flexible sheetat different locations to form an inflatable structure having a head endand a foot end. The structure includes a head portion at the head endand a body portion that extends from head portion to the foot end, withthe first sheet of the structure adapted to support the patient lyingthereon. The head portion has a non-inflatable head area whereupon thehead of the patient lies and the body portion has a non-inflatable bodyarea whereupon at least one portion of the body of the patient lies.There is at least one channel formed in the structure for surroundingthe non-inflatable head area and two other channels each in fluidcommunication with a corresponding opening of the one channel. Each ofthe other channels extends substantially along a correspondinglongitudinal side of the non-inflatable body area. A cross channel isformed at the foot end of the structure to establish a fluidcommunication path between the two other channels. There is an inletthat enables air to be input to the structure and be circulated throughthe channels, and output from the apertures toward the patient lying onthe structure.

Another aspect of the instant invention relates to a convectiveunderbody blanket having a head end and a foot end that comprises: ahead portion extending from the head end having a non-inflatable headarea for receiving the head of a patient, a body portion extending fromthe head portion having a non-inflatable body area for receiving thebody (including a part of the body) of the patient, at least oneinflatable channel at the head portion to surround the non-inflatablehead area, at least two inflatable other channels at the body portioneach in fluid communication with a corresponding opening of the onechannel and each extending substantially along a correspondinglongitudinal side of the non-inflatable body area, an inflatable crosschannel formed at the foot end of the blanket to establish a fluidcommunication path between the other channels, a plurality of aperturesformed at the one and other channels, and at least one inlet provided tothe blanket to enable air to be input into and circulate through thechannels.

The instant invention also relates to a method of manufacturing anunderbody convective blanket that includes the steps of: punching aplurality of apertures on a first air impermeable flexible sheet,selectively bonding the first air impermeable flexible sheet to a secondair impermeable flexible sheet at different locations to form aninflatable structure that has a head end and a foot end, a head portionat the head end that has a non-inflatable head area to receive the headof the patient and a body portion extending from the head portion to thefoot end having a non-inflatable body area to receive the body of thepatient. The bonding step further includes the step of forming at leastone channel in the structure to surround the non-inflatable head area,forming at least two other channels each in fluid communication with acorresponding opening of the one channel, extending each of the otherchannels substantially along a corresponding longitudinal side of thenon-inflatable body area and forming a cross channel at the foot end ofthe structure to establish a fluid communication path between thechannels. The method further includes the step of forming at least oneinlet to the structure to enable air to be input into and to circulatethrough the channels, and to output from the apertures.

BRIEF DESCRIPTION OF THE FIGURES

The present invention will become apparent and the invention itself withbe best understood with reference to the following description of thepresent invention taken in conjunction with the accompanying drawingswherein:

FIG. 1 is a top view of the blanket of the instant invention;

FIG. 2 is a top view of the blanket of the instant invention having apatient lying thereon;

FIG. 3 is another embodiment of the blanket of the instant invention;

FIG. 4 shows a variant of the FIG. 3 embodiment in which multiple setsof apertures are provided along the selected sections of each of thelongitudinal channels;

FIG. 5 shows another embodiment of the inventive blanket where theapertures for outputting air to the patient are provided at the upperportion of the blanket; and

FIG. 6 is another variant of the FIG. 5 blanket where the apertures areprovided at the lower body portion of the blanket.

DETAILED DESCRIPTION OF THE INVENTION

With reference to FIG. 1, a convective underbody blanket 2 is shown tohave a head end 4 and a foot end 6. The blanket is made of two sheets offlexible air impermeable material that are bonded together. The bondingof the first or top flexible air impermeable sheet to the second orbottom flexible air impermeable sheet is done by seals such as 8, 8′ and8″ shown. Seal 8 designates the outer seal that forms the outerperiphery of blanket 2. Seal 8″ designates the seals that, together withseal 8, form the outer flaps 16 a and 16 b of the blanket. Seal 8′designates the internal seals of the blanket. Thus bonded, the flexibleair impermeable sheets form blanket 2 that has a head portion 10 and abody portion 12.

In head portion 10 there is a non-inflatable head sub-portion, or area14. Non-inflated head area 14 is surrounded by a channel 18 that has twoopenings 20 and 20′. It should be appreciated that even though only onechannel 18 (which includes to be discussed lower channel 18′) is shownto surround head area 14, there may in practice be a multiple number ofchannels 18 formed at the head portion 10 to circumscribe head area 14.

As shown, there are three rows of air apertures 22, 22′ and 22″ thatsubstantially surround the head portion of the non-inflatable head area14. There are in addition two rows of apertures 24 and 24′ that arelocated at the lower portion of the non-inflatable head area 14, whichhappens to be the lower portion of channel 18, designated 18′. For theblanket embodiment shown in FIG. 1, channel 18 therefore substantiallycircumscribes the non-inflatable head area 14, except for openings 20and 20′. The rows of apertures 22 (including 22′ and 22″) are arrangedsuch that when channel 18 is inflated, due to the flexible nature of theupper sheet, apertures 22 would substantially shift or orient upwardlyat an angle relative to the horizontal plane of the blanket as channel18 rises. The apertures end up pointing towards the non-inflatable area14 at an angle, after channel 18 has been substantially fully inflated.The apertures would direct the air circulating in channel 18 out towardsthe non-inflatable area 14, and therefore focus the warm air to the headof the patient lying thereon. Apertures 24 at the lower head portionprovide heat to the neck and head of the patient.

The body portion 12 of blanket 2 extends from head portion 10 to thefoot end 6. As shown, the body portion 12 has a non-inflatable body area26 that extends substantially from the head portion, or channel 18′, tosubstantially the foot end 6. For the FIG. 1 embodiment, there may beprovided in either or both of the non-inflatable head area 14 andnon-inflatable body area 26 at least one optional fluid absorbent padfor absorbing fluids, which may result from sweat and/or other fluidsfrom the patient, or some other source, collected on the blanket. Asshown in the exemplar blanket of FIG. 1, there are four fluid absorbentpads 27 provided at body area 26. These pads may be attached to theblanket by tape, Velcro or other types of adhesive. Although not shown,at least one fluid absorbent pad may likewise be attached to head area14.

Surrounding body area 26, at each longitudinal sides thereof arerespective pairs of longitudinal channels 28 a, 28 b and 30 a, 30 b.Channels 28 a and 28 b are formed adjacent to body area 26 and areisolated therefrom by seal 8′a. Channels 30 a and 30 b are furtherremoved from body area 26 and are separated from channels 28 a and 28 b,respectively, by seals 8′b ₁ and 8′b ₂. In place of two channels 28 and30, the inventive blanket may utilize only one or more than two channelsalong each longitudinal side of body area 26. Empirical studies show twopairs of adjacent channels to be desirable in that the warming of thepatient lying on the blanket continues to be good while the verticalprofile of the inflated blanket is lowered to an acceptable height. Forexample, instead of a six inch rise for a single channel at each side ofthe patient body area 26, with two adjacent channels, the rise in thevertical profile of the blanket would only be approximately 3 incheswhen the blanket is fully inflated.

Provided along each of the longitudinal channels 28 and 30 areapertures, in most instances evenly spaced, that extend in a row alongthe length of each of the channels. The apertures are biased towards thenon-inflatable body area 26. These rows of apertures are designated 32 aand 32 b (for channels 28 a and 28 b, respectively) and 34 a and 34 b(for channels 30 a and 30 b, respectively). Each of the rows ofapertures 32 a, 32 b 34 a and 34 b is arranged along its correspondingchannel such that when the channels are inflated, the respective rows ofapertures will orient at an angle, relative to the horizontal plane ofthe blanket, towards the non-inflatable body area 26. As a consequence,air output from the apertures is directed to the body area 26, andfocused to particular portions of the body of the patient lying thereon.

As was discussed above, apertures 22, 32 and 34 are pre-punched in thetop air impermeable sheet so that when the top sheet is bonded to thebottom sheet, the rows of apertures 22, 32 and 34 would liesubstantially adjacent their respective seal lines 8′, 8′a ₁ and 8′b ₁,respectively. This ensures that when the blanket is inflated, as therespective channels containing the apertures are inflated, therespective rows of apertures would be orientated towards the head area14 and the body area 26. Of course, if there are additional channels,additional rows of apertures similarly arranged would be added. Also, aswas noted before, instead of dual channels 28 and 30, if the blanketprofile height is of no importance, there may only be one longitudinalchannel provided along either side of body area 26.

As shown in FIG. 1, channels 28 a and 30 a each are in fluidcommunication with channel 18, 18′ by way of opening 20, while channels28 b and 30 b each are in fluid communication with channel 18, 18′ viaopening 20′. Channels 28 and 30 from each side of body area 26 extendsubstantially from the head portion to the lower portion of the blanketproximate to seal 8′a ₁, by way of their respective seal ends 8′b ₁′ and8′b _(2′).

A cross channel 36 is formed at foot end 6 between seal 8′a ₁ and thelowermost seal 8 a. Thus formed, the cross channel 36 establishes athrough passage or fluid communications path for channels 28 a, 30 a andchannels 28 b, 30 b. The non-inflatable body area therefore iscircumscribed by through passages in the form of channels 28, 30 and 36,as well as channel 18′; while the non-inflatable head area 14 iscircumscribed by channels 18 and 18′. Given that channel 18 and channels28, 30 are interconnected, when the blanket is inflated by pressurizedheated air and the blanket inflation is maintained, the heated air iscirculated throughout the blanket. Thus, the temperature of the heatedair remains substantially the same throughout the blanket. Accordingly,temperature gradient differences among the various areas of the blanketthat exist in prior art convective blankets are substantiallyeliminated, as the heated air output from the various rows of aperturesto bathe the patient for the inventive blanket has substantially thesame temperature, for example within 1 to 5° centigrade difference.

To enable air to be input to blanket 2, there is at least one air inletprovided. For the inventive blanket of FIG. 1, three inlet ports 38 a,38 b and 38 c are provided. Inlet ports 38 a and 38 b each are providedat a corresponding shoulder section of blanket 2, while inlet port 38 cis provided at the foot end of blanket 2. Each of those air inlets maybe made of a foldable hose retainer port described in greater detail inthe above incorporated by reference application Ser. No. 11/401,957. Byhaving a multiple number of air inlet ports, the anaesthesiologist isable to arrange his equipment at multiple locations relative to blanket2.

In operation, the selected air inlet port may be folded into a box shapeto accept an air hose (not shown) so that pressurized heated air may beforce fed into the blanket by a hot air blower, such as for example theEQUATOR convective air warmer sold by the assignee of the instantinvention.

FIG. 2 shows a patient 38 resting on blanket 2. As shown, the head ofthe patient is resting on the non-inflatable head area 14 (shown moreclearly in FIG. 1) while the body of the patient is resting on thenon-inflatable body area 26. Given the positioning of the patient onblanket 2, it can readily be seen that the heated air output from thedifferent rows of apertures 22 is directed to the head of a patientwhile the air output from the rows of apertures 32 a, 32 b and 34 a, 34b is directed to warm the body of the patient.

Presuppose the pressurized and presumably heated air is input to theblanket via inlet port 38 b. The input air therefore would circulatethrough channels 18, 18′, 28 and 30, and 36 around the blanket. Once theblanket is fully inflated and the input air maintains the channels atequilibrium inflation, the air output from the various apertures wouldtend to have substantially the same temperature, or substantially thesame temperature gradient (for example from ambient to 44° c. at the airinlet location to ±5° c. variance across the blanket), to warm thepatient. By providing multiple rows of apertures at head portion 10, thehead of the patient is exposed to more heated air. To secure the blanketto the bed or the operating table, flaps 16 a and 16 b at the sides ofthe blanket may be taped or tied to the bed or the operating table.

FIG. 3 shows an alternative embodiment of the instant invention wherethe respective rows of apertures at the longitudinal channels 28 and 30are discontinuous. Putting it differently, each of those rows ofapertures is made up of two sets or two sections of apertures separatedby a non-apertured section. Point of illustration. At channel 28 a, whatused to be a row of apertures 32 a is now divided into aperturedsections 32 a ₁ and 32 a ₂, separate by a non-apertured section 32 a ₃.The same apertured sections separated by a non-apertured section layoutis repeated for channels 32 a, 28 b and 30 b of blanket 2. For ease ofillustration, only the sections of channels 28 a and 30 b are numberedin the FIG. 3 embodiment blanket.

With no apertures provided at the non-apertured section such as 32 a ₃and 34 b ₃, no air is output from those portions of the blanket. This isadvantageous in the instance where the surgeon operating on the patientdoes not want to be heated by the warm air output from the convectiveblanket. By thus removing the air apertures from those sections of theblanket as shown, which happens to be where the surgeon usually ispositioned relative to the patient when he or she operates on thepatient, the surgeon is not directly heated by the air output from theblanket. Also, there may be instances where the area of the patient thatis being operated on should not be directly subjected to heated air.With the blanket embodiment of FIG. 3, the being operated area of thepatient no longer is directly exposed to heated air. Instead, that areaof the patient is heated by air conduction, whereas the remainder of thepatient continues to be directly warmed by heated air output from theapertures in a convective manner.

FIG. 4 is an illustration of a blanket that is a variant of theembodiment of the blanket shown in FIG. 3. Elements that correspond tothose in the FIG. 3 embodiment are labeled the same. In particular,instead of respective discontinuous single rows of apertures along eachof the longitudinal channels 28 a, 28 b and 30 a, 30 b, there are showntwo discontinuous parallel rows of apertures along each of the channels.To illustrate, for channel 28 a, a non-apertured section 32 a 3 issandwiched by a set of double rows of apertures at section 32 a 1 and aset of double rows of apertures at section 32 a 2. The same is true forall of the other channels 30 a, 28 b and 30 b shown. Similar to thepreviously discussed embodiments, the apertures of each channel of theblanket are configured such that when the blanket is inflated, theapertures are oriented toward the center of the blanket so that airoutput therefrom is directed to the patient lying on the blanket,presumably on the uninflated body area 26 thereof. Although only tworows of apertures are shown at each of the apertured sections, it shouldbe appreciated that more than two rows of apertures may also be used.So, too, in place of two parallel rows, the apertures may be configuredto be out of alignment with each other at each of the aperturedsections, so long as the non-aligned apertures continue to face towardthe non-inflated body area 26 when the blanket is inflated, such thatair output from the apertures continues to be directed to the patient.

Another difference between the blanket shown in FIG. 4 and those shownin the earlier figures is the respective lengths of the side flaps 16 aand 16 b. For the FIG. 4 blanket, flap 16 a is longitudinally contiguousalong a corresponding side of the outermost longitudinal channel 30 a(i.e., separated by seal 8 a 1), while flap 16 b is longitudinallycontiguous along the side of the outermost longitudinal channel 30 bdefined by seal 8 a 2, up to air inlet 38 c.

Another embodiment of the instant invention is shown in FIG. 5. Allelements that are the same as in the previous embodiments are designatedthe same in this embodiment. As shown, the inventive blanket of the FIG.5 embodiment is configured substantially the same as in the earlierembodiments except for the placement of the apertures or air outletsalong the blanket. For this embodiment, air outlet apertures areprovided at the upper body portion 40 of the blanket so that aircirculating within the blanket is output only to the upper body of thepatient lying on the blanket. The apertures are configured and punchedas described in the earlier embodiments of the instant invention so thatwhen the blanket is substantially fully inflated, the orientation of theapertures, for example the two rows of the apertures designated 42 atchannel 30 b is directed to the non-inflatable area 26 so that the airoutput from the apertures is substantially directed to the upper body ofthe patient. This is useful in those situations where only the upperbody of the patient is to be warmed. As shown in FIG. 5, only the rowsof apertures in channels 30 b and 28 a are labeled, i.e., 42 for channel30 b and 44 for channel 28 a. The other apertures shown in FIG. 5 havenot been labeled for ease of illustration. Although two rows ofapertures are shown at each of the longitudinal channels that sandwichnon-inflated body area 26, it should be appreciated that only one row ormore than two rows of apertures may be formed at each of thelongitudinal channels at the upper body portion 40 of the blanket forbathing the upper body of the patient with the air output from thoseapertures.

A variant of the FIG. 5 embodiment is shown in FIG. 6. There, instead ofbeing provided at the upper body portion of the blanket, the aperturesare provided at the lower body portion 46 of the blanket. Same asbefore, for ease of illustration, only the apertures 48 along channel 30a and apertures 50 along channel 28 b are labeled. As before, instead ofthe dual parallel rows of apertures provided along the longitudinalchannels, only one row or additional rows of apertures may be providedat each of the longitudinal channels for outputting air from the blanketto warm the lower body portion of the patient lying on the blanket. Theconfiguration of the apertures 48 and 50 for the FIG. 6 embodiment issimilar to those of the earlier embodiments so that, when the blanket issubstantially fully inflated, the apertures would orient toward thenon-inflatable body 26 and air output from those apertures is directedsubstantially only to the lower body portion of the patient.

The present invention is subject to many variations, modifications andchanges in details. For example, instead of dual longitudinal channels,there may only be one channel along each side of the non-inflatable bodyarea. Conversely, there may be more than two channels extendinglongitudinally along each side of the non-inflatable body area. Further,even though only one row of apertures is shown along each of thelongitudinal channels, there may in practice be multiple rows ofapertures, either continuous evenly spaced rows of apertures or sectionsof evenly spaced apertures separated by a non-apertured section, biasedin the same manner towards the patient body area per shown in theFigures. Thus, it is intended that all matter described throughout thisspecification and shown in the accompanying drawings be interpreted asillustrative only and not in a limiting sense. Accordingly, it isintended that the instant invention be limited only by the spirit andscope of the hereto appended claims.

1-16. (canceled)
 17. A method of manufacturing an underbody convectiveblanket comprising the steps of: a) punching a plurality of apertures ona first air impermeable flexible sheet; b) selectively bonding saidfirst air impermeable flexible sheet to a second air impermeableflexible sheet at different locations to form an inflatable structurehaving a head end and a foot end, a head portion at the head end havinga non-inflatable head area to receive the head of the patient and a bodyportion extending from said head portion to the foot end having anon-inflatable body area to receive the body of the patient; whereinsaid bonding step further includes the steps of forming at least onechannel in said structure to surround said non-inflatable head area;forming at least two other channels each in fluid communication with acorresponding opening of said one channel; extending each of said otherchannels substantially along a corresponding longitudinal side of saidnon-inflatable body area; forming a cross channel at the foot end ofsaid structure for establishing a fluid communication path between saidother channels; and c) forming at least one inlet to said structure toenable air to be input to and be circulated through the channels, andoutput from the apertures.
 18. Method of claim 17, wherein said punchingstep (a) further comprises the steps of: punchingly arrange at least onerow of apertures along said one channel so that said one row ofapertures would orient towards the non-inflatable head area when saidone channel is inflated; and punchingly arrange at least two other rowsof apertures each along a corresponding one of said other channels suchthat each of said other rows of apertures are oriented towards saidnon-inflatable body area when said other channels are inflated. 19.Method of claim 17, wherein said bonding step (b) further comprises thesteps of: forming at least a pair of first and second other channelslongitudinally along each side of said non-inflatable body area; andarranging at least one row of apertures at each of said first and secondchannels such that the apertures are oriented towards saidnon-inflatable body area to direct air output from the apertures towardssaid non-inflatable body area when said first and second channels areinflated.
 20. Method of claim 17, wherein said punching step (a) furthercomprises the steps of: punching at least two in alignment sections ofapertures separated by a non-apertured section longitudinally along eachone of said other channels; and arranging said sets of apertures alongeach of said other channels such that when said other channels areinflated, the apertures are oriented towards said non-inflatable bodyarea to direct air output from the apertures towards said non-inflatablebody area, no air being output from said non-apertured section of eachof said other channels.
 21. Method of claim 17, wherein said bondingstep (b) further comprises the step of: providing at least a pair offirst and second other channels longitudinally along each side of saidnon-inflatable body area; and wherein said punching step furthercomprises the steps of: punching prior to said providing step two inalignment sections of apertures separated by a non-apertured section forsaid first and second other channels; and arranging the apertures atsaid first and second other channels to orient towards saidnon-inflatable body area when said first and second channels areinflated so that air output from the apertures is directed in adirection towards said non-inflatable body area, no air being outputfrom said non-apertured section of said first and second channels. 22.Method of claim 17, further comprising the step of: positioning at leastone fluid absorption pad at least one of said non-inflatable areas toabsorb fluid collected thereat.
 23. Method of claim 17, wherein saidforming step {circle around (c)} further comprises the step of:providing two inlets each at a corresponding shoulder of said structureand a third inlet at the foot end of said structure, each of the inletsadapted to be selectively opened to enable air to be input to saidstructure. 24-27. (canceled)
 28. Method of claim 17, wherein said step(a) comprises the step of punching said plurality of apertures at anupper area of said body portion so that upon bonding of said flexiblesheets, at least one row of apertures is provided along each of saidother channels at the upper body portion of said blanket for outputtingair substantially directed only to the upper body of the patient. 29.Method of claim 17, wherein said step (a) comprises the step of punchingsaid plurality of apertures at a lower area of said body portion so thatupon bonding of said flexible sheets, at least one row of apertures isprovided along each of said other channels at the lower body portion ofsaid blanket for outputting air substantially directed only to the lowerbody of the patient.